Commercially available solutions for wireless power transmission include inductive charging and also magnetic resonance techniques, that differ mainly in their operating frequency ranges while having very similar physical principals. In these solutions, an electromagnetic field is generated at a transmitting coil with a compatible receiving coil that is configured for the generated field. Thus, power can be wirelessly transferred to the receiving coil, via the electromagnetic field.
In order to increase the vertical range between the transmitting coil and the receiving coil, power repeaters are sometimes used. A power repeater is configured to operate in a predetermined frequency compatible with the transmitting coil, such that power can be wirelessly induced in the receiving coil from the repeater instead of being directly induced from the transmitting coil.
The repeater is a passive element in the circuit, with the repeater powered with induction from the transmitting coil. The magnetically induced current in the repeater creates a magnetic field of its own, such that this magnetic field of the repeater can be utilized to induce current in the receiving coil. Thus, the passive repeater(s) can be utilized to extend the active vertical range of the power transmission. However, even with such repeaters it would be advantageous to increase the lateral working range for the wireless power transmission.